Database creation and selection in MySQL - Mini Project: Build & Apply

Database creation and selection

📖 Scenario: You are setting up a new database for a small bookstore. You need to create the database and then select it to start adding tables and data.

🎯 Goal: Create a new database called bookstore and then select it for use.

📋 What You'll Learn

Create a database named bookstore

Select the bookstore database to use

💡 Why This Matters

🌍 Real World

Creating and selecting databases is the first step in managing data for any application, like websites or inventory systems.

💼 Career

Database administrators and developers often create and select databases to organize and manage data efficiently.

1

Create the database

Write a SQL statement to create a database named bookstore.

MySQL

-- Your code here to create the database named bookstore

Hint

Use the CREATE DATABASE command followed by the database name.

2

Select the database

Write a SQL statement to select the database named bookstore for use.

MySQL

CREATE DATABASE bookstore;
-- Your code here to select the bookstore database

Hint

Use the USE command followed by the database name to select it.

3

Verify the current database

Write a SQL statement to show the name of the currently selected database.

MySQL

USE bookstore;
-- Your code here to show the current database

Hint

Use the SELECT DATABASE() function to see the current database.

4

Drop the database (optional cleanup)

Write a SQL statement to drop the database named bookstore if you want to remove it.

MySQL

USE bookstore;
SELECT DATABASE();
-- Your code here to drop the bookstore database

Hint

Use the DROP DATABASE command followed by the database name to delete it.

Practice

1. What does the CREATE DATABASE command do in MySQL?

easy

A. It selects a database to use.

B. It deletes an existing database.

C. It creates a new database to store data.

D. It shows all databases available.

Solution

1. Step 1: Understand the purpose of CREATE DATABASE

   This command is used to make a new database where you can store tables and data.

2. Step 2: Differentiate from other commands

   Deleting databases uses DROP DATABASE, selecting uses USE, and showing uses SHOW DATABASES.

3. Final Answer:

   It creates a new database to store data. -> Option C

4. Quick Check:

   CREATE DATABASE = create new database [OK]

Hint: Remember: CREATE makes new, USE picks existing [OK]

Common Mistakes:

• Confusing CREATE with USE command
• Thinking CREATE deletes databases
• Mixing CREATE with SHOW DATABASES

2. Which of the following is the correct syntax to select a database named shop in MySQL?

easy

A. SELECT DATABASE shop;

B. CHOOSE DATABASE shop;

C. OPEN DATABASE shop;

D. USE shop;

Solution

1. Step 1: Recall the command to select a database

   In MySQL, the command to start using a database is USE database_name;.

2. Step 2: Check each option's syntax

   Only USE shop; is valid syntax. Others are incorrect commands.

3. Final Answer:

   USE shop; -> Option D

4. Quick Check:

   USE selects database [OK]

Hint: Use USE to pick your database [OK]

Common Mistakes:

• Using SELECT instead of USE
• Trying OPEN or CHOOSE commands (not valid)
• Missing semicolon at end

3. What will be the result of the following commands?

CREATE DATABASE testdb;
USE testdb;
SHOW TABLES;

medium

A. Lists all tables in the database 'testdb'.

B. Shows an error because 'testdb' does not exist.

C. Creates a table named 'testdb'.

D. Shows all databases available.

Solution

1. Step 1: Create and select the database

   The command CREATE DATABASE testdb; makes a new database named 'testdb'. Then USE testdb; selects it for use.

2. Step 2: Show tables in the selected database

   SHOW TABLES; lists all tables in the current database. Since 'testdb' is empty, it will show an empty list but no error.

3. Final Answer:

   Lists all tables in the database 'testdb'. -> Option A

4. Quick Check:

   SHOW TABLES lists tables in current DB [OK]

Hint: SHOW TABLES lists tables in current database [OK]

Common Mistakes:

• Thinking SHOW TABLES shows databases
• Assuming error because database is new
• Confusing CREATE DATABASE with CREATE TABLE

4. Identify the error in the following MySQL commands:

CREATE DATABASE mydb
USE mydb;

medium

A. Database name 'mydb' is invalid.

B. Missing semicolon after CREATE DATABASE statement.

C. USE command cannot follow CREATE DATABASE.

D. CREATE DATABASE should be lowercase.

Solution

1. Step 1: Check syntax of each command

   MySQL commands must end with a semicolon. The first line misses a semicolon after CREATE DATABASE mydb.

2. Step 2: Verify other parts

   The database name 'mydb' is valid, USE can follow CREATE DATABASE, and case does not matter for commands.

3. Final Answer:

   Missing semicolon after CREATE DATABASE statement. -> Option B

4. Quick Check:

   Semicolon ends commands [OK]

Hint: Always end SQL commands with semicolon [OK]

Common Mistakes:

• Forgetting semicolon at end of statements
• Thinking database names must be uppercase
• Believing USE cannot follow CREATE DATABASE

5. You want to create two databases named sales and inventory, then select sales to work with. Which sequence of commands is correct?

hard

A. CREATE DATABASE sales; CREATE DATABASE inventory; USE sales;

B. USE sales; CREATE DATABASE sales; CREATE DATABASE inventory;

C. CREATE DATABASE sales, inventory; USE sales;

D. CREATE DATABASE sales; USE inventory; CREATE DATABASE inventory;

Solution

1. Step 1: Create both databases separately

   Each database must be created with its own CREATE DATABASE command ending with a semicolon.

2. Step 2: Select the 'sales' database to use

   After creating, use USE sales; to select the 'sales' database for work.

3. Final Answer:

   CREATE DATABASE sales; CREATE DATABASE inventory; USE sales; -> Option A

4. Quick Check:

   Create each DB then USE the one you want [OK]

Hint: Create each DB separately, then USE the desired one [OK]

Common Mistakes:

• Trying to create multiple databases in one command
• Using USE before creating the database
• Selecting wrong database after creation